Change color of Icon for un-clustered markers in Mapbox IOS

Question

I am trying to implement clustering in Mapbox in IOS. I want to change color for unclustered StyleLayer depending on specific attribute in MGLPointFeature. following is the code for single feature :

let feature = MGLPointFeature()
feature.coordinate = CLLocationCoordinate2D(latitude: site.latitude, longitude: site.longitude)
feature.attributes = ["id": site.siteId, "siteCode": site.siteCode, "risk": site.riskId]

in above snippet, I want to use this attribute ("risk": site.riskId) to generate different colors for icon which is set by using following code:


style.setImage(icon.withRenderingMode(.alwaysTemplate), forName: "icon")

let ports = MGLSymbolStyleLayer(identifier: "ports", source: source)
ports.iconImageName = NSExpression(forConstantValue: "icon")    
ports.predicate = NSPredicate(format: "cluster != YES")
ports.iconAllowsOverlap = NSExpression(forConstantValue: true)
style.addLayer(ports)

and following are the colors for each riskId :

let risks = [
        0: Color.cellBackgroundColor,
        1: UIColor.from(hexString:  "B9E5D1"),
        2: UIColor.from(hexString:  "95E9FF"),
        3: UIColor.from(hexString:  "FCE2A6"),
        4: UIColor.from(hexString:  "FCE2A6")
    ]

I have an idea that I can get these results using NSExpression for feature attributes. But have no idea how to implement it. Can anyone please help me get this done. Thanks

Sohail Ahmad Khan Sohail Ahmad Khan · Accepted Answer · 2020-08-21T09:01:44

So, I was able to solve this problem. For this I added an attribute "siteRiskColor" in Feature and gave it the value depending on value of risk as

let riskId = site.riskId
            var color = "B0E5A1"
            if  riskId == 1 {
                color = "B0E5A1"
            } else if riskId == 2 {
                color = "99E9FF"
            } else if riskId == 3 {
                color = "FCD2A6"
            } else if riskId == 4 {
                color = "FBC3A9"
            }

and then added different images for each color mentioned above and name them same as above. Then, while making icon for un-clustered style image I added following lines to pick different images.

let site = MGLSymbolStyleLayer(identifier: "site", source: source)
 site.iconImageName = NSExpression(forKeyPath: "siteRiskIcon")

and it worked!

Change color of Icon for un-clustered markers in Mapbox IOS

1 Answers